The goal of this research is to determine some of the information that chimpanzees can recall and report about the nature and location of objects in outdoor environments. Four chimpanzees will be tested. The animals are uniquely well-suited for studies of recall memory. They have learned arbitrary visual symbols (lexigrams) that refer to foods and other objects, and some can use the lexigrams outside the context in which they encountered the objects. The following method will be used to assess recall memory. An animal sees an experimenter place an object in an outdoor location. Later, in its indoor cage, the animal can indicate to an uninformed person the type, location, quality, and other attributes of the object and who put it out. The delay between the cue-giving and response phases of the trial will range up to 4 weeks. To assess forgetting, some objects will be removed once the animal "reports" them, whereas others will be replaced. In addition, tasks that an animal can solve in real life situations in the outdoor enclosure will be modeled for presentation to that individual in a computer format. Animals will manipulate a joystick to make a cursor hit a target on a monitor. Targets and/or barriers will disappear as soon as the animal begins to move. The questions are how much detail the animal remembers about the relative positions of targets, landmarks, and barriers, and how efficient its route is. The animal's route will be compared on a jump by jump basis to an optimal routing. The ability to recall information about features of the environment not present to the senses is important in human thinking, planning and communication, and this ability presumably had a major influence on the emergence and evolutionary development of humans, but to date there are almost no data on recall memory capabilities in nonverbal animals.